Seems like he is stuck in idealization mode and creating facades by
MIRRORING people.
Taking selfies is about creating an image, or trying to.This is why poses are often so fake
He has no sense of self, constantly trying to adopt one.
Not sure its narcissism, otherwise he would just assume he is the bees knees rather than trying create the impression.
Sometimes people with BPD can come across as wannabe NPD, as they crave being in control much the same way NPD can take it as a sense of entitlement.
123Phoebe is right in that you can disable yourself by over analysing what is not ultimately affecting you. There is a lot of weird stuff with PDs some has just got to be left as "their stuff' unless it impacts you.